I placed a rack on the bottom to allowfor 7 inches of just water. Then I placed 2 layers of the filter media onto the rack. The filter media is 1 inch thick and is course on the bottom 1/2 inch and finer in the top 1/2 inch. It is supposed to catch solids and the little stuff. After the 2 layers of media is a thick pile of bio balls and then 2 layers of filter media and another thick layer of bio balls. Then there are two more layers of filter media and on top of that is a bunch of media cut into small squares and just piled in there. Then I added the grate on top to keep the media below my pumps out line. I put the water in the filter about a week ago and added the bacteria starter liquid. The water has a little bit of a funny smell kinda like fish with some stink added. I hope that's the bacteria growing like crazy and that it's the good kind.
